Cutting oil composition



Patented Dec. 31, 1946 STATES PATENT OFFICE I 2,413,353 CUTTING on.COMPOSITION Benjamin F. Hunter and Harold P. Hobart, Pittsburgh, Pa.,assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation ofPennsylvania N Drawing. Application May 25, 1943; Serial No. 488,428

portant to lessen wear on tools, to diminish the energy input required,to improve thefinish of the shaped articles, to permit shaping articlesto accurate dimension, and to permit the use of relatively high cuttingspeeds. The more viscous cutting oils which have viscosities of 100SUVor more at 210 F. are satisfactory for many of these cutting operations.However, where excessive heat is generated, for example'in the cuttingof aluminum and brass and certain types of steels, the heat removal bymore viscous oils may not be sufficiently rapid to permit the use ofhigh cutting speeds and the production of satisfactory surfaces onthecut articles. On the other hand light mineral oils such as have beenused heretofore, while they have high heat removal capacity, are lessdense than the more viscous oils and their lubricity and extremepressure characteristics are such that greater power input is requiredand greater tool wear results.

bile and have high heat removing capacity and.

which at the same time have good lubricity and extreme pressurecharacteristics. It is a further object achieved by the presentinvention to provide improved cutting oil compositions usefulparticularly in cutting operations on aluminum, brass and certain typesof steels whereby there is obtained an improved finish on the cutproducts. It is also an object of this invention to provide improvedcutting oil compositions useful as additives for the commerciallyavailable cutting oils, to improve their heat removal properties, theirlubricity and extreme pressure charastei'istics whereby tool wear islessened, energy consumption is diminished, improved finish and improvedaccuracy of dimensions are obtained, even at high cutting speeds.

We have found that by incorporating in a light non-viscous mineral oil arelatively small amount of a viscous mineral lubricatingoil having aSaybolt Universal viscosity of at least about 100 4 Claims. (Cl. 252-56)at 210 F. and a small amount of an antioxidant I adapted to preventoxidational deterioration of mineral oils, and advantageously containingalso a small percentage of a residue obtained from the solvent refiningof distillate oils, a cutting oil composition having particularlyadvantageous properties for use in the cutting of aluminum, magnesium,brass, copper and other non-ferrous alloys and certain steels isobtained. We have 'found also that cutting oil compositions of thisgeneral type are particularly adapted for blending with heavier cuttingoils of the types commercially available, with substantial improvementin the properties which recommend their use in the cutting of suchmetals.

As a base oil for the cutting oil compositions of our invention, lightmineral oils having viscosities and boiling ranges at least as high asvthose of kerosene and advantageously not greater than those of the verylight lubricating oils such as mechanism oil, have been found mostsatisfactory. In general mineral oil fractions boiling above about 350F. and having viscosities less than about 40-SUV at 100 F. have beenfound most useful. A particularly advantageous form of light oil is theproduct known as mineral seal oil, atypical example of which has an APIgravity of 41.0, a flash oint of about 260 F., a fire point of about 300F., a viscosity at 100 F. of 38.7 SUV and a pour point of about +25? F.In compounding the cutting oil compositions of our invention these lightoils are used in amounts corresponding to at least about 50 per cent byweight and advantageously in amounts corresponding to about to 97.5 percent by weight.

Various types .of fixed fatty oils may be used in the cutting oilcompositions of our invention. These oils are intended primarily toincrease the oiliness or lubricity of the resultant composition andare'customarily used in amounts corresponding to 0.5 to 15.0 per cent byweight. Lard oil is particularly satisfactory for this purpose. However,other animal oils such as tallow oil, neats-foot oil, sperm oil, wooloil, whale oil and the like may be used. Also certain fish andvegetableoils may be used. The fish oils are generally less advantageous due totheir ofiensive odor and the vegetable oils are likewise lessadvantageous because of their tendency to oxidize and form gum at thetemperatures encountered.

in cutting operations. However, by the use of a sufficient amount ofoxidation inhibitor this defect may be minimized and vegetable oilssuchas olive oil, rapeseed oil, corn oil and castor oil may be used.

, compounds.

The addition of the high viscosity petroleum maintained by the highviscosity petroleum oil present. A lubricating oil having a' viscosityof about 150 SUV at 210' F. is most satisfactory but oils ranging inviscosity from about 100 to' 200 SUV at 210 F. may be used. Typically 2per cent of the highly viscous oil is used in the cut-v 1 ting oilcompositions of our invention, but amounts between 1 and per cent may beused with advantage.

The oxidation inhibitor used in the compositions of our inventicmincreases the useful life of the cutting oil and decreases any tendencyto thicken due to the formation of sludge or gum. Substantially any ofthe oxidation inhibitors heretofore used for the prevention ofoxidational deterioration of petroleum oil compositions may be used, forexample, the amino phenols, the alkylated phenols, the alkyl phosphitesand the alkylated phenol phosphite and phosphate esters. The latterclass, particularly the alkyl phenyl phosphite esters, are alsoeffective in increasing the extreme pressure characteristics of mineraloil compositions to which they are added. For this reason we have foundthese compounds most advantageous for use in the cutting oilcompositions of our invention. Typical compounds which have provedsatisfactory are triJtertiary-amylphenyl) -phosphite, triebutylphosphite and similar compounds. The extreme pressure characteristicsimparted by the addition of this class of phosphite oxidation inhibitorsincrease the polishing action obtainable with the cutting oilcompositions of our invention and minimize the scuf flng or tearingaction on the metal. The antioxidants are advantageously incorporated inthe cutting oil compositions in amounts from 0.03 to 5 per cent byweight.

By incorporating a small amount of each of the. above components that isa fixed fatty oil, a relatively heavy lubricating oil and an oxidationinhibitor, particularly of the phosphite type. in a predominant amount'of a mineral seal oil or other light mineral oil fraction cutting oilcompositions having the desired properties can be obtained. We havefound, however, that it is generally advantageous to incorporate also arelatively small amount of a residual material obtained by the solventextraction. of petroleum oil distillates. In the solvent refining ofdistillate petroleum oils, particularly for use as lubricating oils,extraction with furfural, nitrobenzene, sulfur dioxide, phenols and thelike is-often resorted to for the removal of certain undesiredcomponents, including polycyclic hydrocarbons and certain sulfur Theseextracted materials, when incorporated in the cutting oil compositionsof our invention, are also effective to increase their extreme pressurecharacteristics. Furthermore, in view of the fact that the sulfurcontent in these compounds is closely combined, there is little or notendency of the resulting cutting oils to cause tarnishing ordiscoloration of out metal surfaces on which they are used. Solventrefining extracts obtained from distillate oils and having viscositiesof 55 to 70 SUV at 210 F. have been found most useful. These distillateoil extracts, while advantageous in the compositions of our invention,are not essential components thereof,

. 4 but when used may be incorporated with advantage in amounts up toabout 10.0 per cent by weight. A typical residual product of this typewhich has been found suitable for the composi- 113 of our invention hasthe following prope es:

-AP I gravity, 14.4 Flash point F. 365 Fire point F 435 Viscosity at 100F "SUV" 1222 Viscosity at 210 F sUv 61.8 Pour point IL- +5 Other extremepiessure agents may also be used in the compositions of. our-invention,such as sulfurized fatty oils or sulfurized mineral oil bases containingnot only the chemically combined but also dissolved sulfur, orchlorinated organic compounds, and the like. However, for cutting oilcompositions to be used in conjunction with readily tarnishable orreadily discolored metal surfaces it is generally undesirable to useextreme pressure agents containing loosely combined or dissolved sulfuras such sulfur tends to mar the cut surfaces. I

Variousother components may be incorporated in the cutting oilcompositions of our invention if desired, to improve other specificproperties without deleteriously afiecting the primary combination ofproperties of high capacity for heat removal, good lubricity and goodextreme pressure characteristics, which characterize the cutting oilcompositions of our invention. For example, wetting agents such as fattyacids and in accordance with our invention act as energizers for theheavier cutting oil compositions. They have the property of increasingthe penetration,-wetting ability and cooling effect of such cuttingoils. They are advantageously used in amounts corresponding to about 10to 30 parts by weight on th mixture, although good'results may also beobtained with greater or lesser .amounts.

In the following specific example there are illustrated the resultsobtainable with the cutting oil compositions prepared in accordance withpour point l Tri-(tertiary-amyl-phenyl) -phosphite 0.05

Oil of citronella (scenting agent) 0.01

- oil.

. The resulting composition had an API gravity of 39.6, a flash point of270 F., a fire point of 305 F., a viscosity of 40.9 SUV at 100 F., and apour point of F.

This composition was employed in the tapping of aluminum castings incomparison with commerical cutting oil A, a soluble cutting oil used inan emulsion in water. castings were tapped using each of the cuttingoils. In the case of the castings using the commercial cutting oilemulsion, castings were lost due to inadequate lubrication, while withthe cutting oil compositions of the present invention no castings werelost from this cause. In other words, one casting out of every twentywas lost due to cracking or other damage caused by overheating orinadequate lubrication using the commercial cutting oil emulsion, whileno castings were lost out of 500 processed using the composition of thepresent invention.

It was found in further tests that the speed of cutting aluminum couldbe increased 15 to 20 per cent without deleterious eifect using thecutting oil of the present invention and the tool life could belengthened up to 75 per cent. Also it was found in these tests that thecut aluminum surface had a high finish resembling that obtained in apolishing operation.

The cutting oil composition prepared according to the present inventionwas mixed in the proportion of 10 per cent with 90 per .cent ofcommercial cutting oil B, which was a cutting oll containing about 3 percent of sulfur and having a viscosity of about 100 SUV at 210 F.Comparative tests were then made between the re- Monel metal increasedtool life by 250 per cent and reduced the cutting time 45 per cent overthe results obtainable with the unblended cutting A third blended oilwas prepared by mixing 15 parts of the cutting oil composition of thepresent invention with 85 parts of commercial cutting oil C, which had aviscosity of about 70 SUV at 210 F. and contained sulfurized lard oiland free and combined sulfur to a total of about 2 per cent. This blendwhen used in connection with the drilling of SAE-X4130 steel having aRockwell C hardness of 38 to 40 increased the service of the drill 200to 300 percent.

Another blended cutting oil was prepared by mixing one part of thecutting oil composition above outlined with commercial cutting oil D,corresponding in composition to commercial cutting oil C above buthaving a slightly higher viscosity. When used in connection with theborin and reaming of 4150 steel this blend gave a per cent increase intool life.

While this invention has been described herein with respect to certainspecific embodiments hereof, it is to be understood that the inventionis not limited to the details of such embodiments eizcept as hereinafterdefined in the appended c aims.

In this cutting test 500 What we claim is:

1. An improved cuttingoil composition comprising at least about 50.0 percent by weight of a light mineral oil boiling above about 350 F. andhaving a viscosity not greater than about 40 SUV at 100 F., from about1.0 to about 20.0 per cent by weight of a mineral oil having a viscositybetween about 100 and about 200 SUV at 210 F.,

- from about 0.5 to about 15.0 per cent by weight of a fixed fatty oil,from about 0.03 to about 5.0 per cent by weight of a petroleum oilanti-oxidant, and up to about 10.0 per cent by weight of the residuewhich remains after removal of the solvent from the extract obtained byextracting a petroleum distillate oil with a solvent capable of removingpolycyclic hydrocarbons and sulfur compounds from petroleum distillateoils, said residue having a viscosity between about 55 and about SUV at210 F.

2. An improved cutting oil composition comprising at least about 5.0 percent by weight of a light mineral oil boiling above about 350 F. andhaving a viscosity not greater than about 40 .SUV at F., from about 1.0to about 20.0 per cent by weight of a mineral oil having a viscositybetween about 100 and about 200 SUV at 210 F., from about 0.5 to about15.0 per cent by weight of lard oil, from about 0.03 to about 5.0 percent by weight of a petroleum oil anti-oxidant, and up to about 10.0 percent by Weight of the residue which remains after removal of the solventfrom the extract obtained by extracting a petroleum distillate oil witha solvent capable of removing polycyclic hydrocarbons and sulfurcompounds from petroleum distillate oils, said residue having aviscosity between about 55 and about 70 SUV at 210 F.

3. An improved cutting oil composition comprising at least about 50.0per cent by weight of a light mineral oil boiling above about 350 F. andhaving a viscosity not greater than about 40 SUV at 100 F., from about1.0 to about 20.0 per cent by weight of a mineral oil having a viscositybetween about 100 and about 200 SUV at 210 F., from about 0.5 to about15.0 per cent by weight of lard oil, from about 0.03 to about 5.0.percent by weight of tri(tertiary-amyl-phenyl) -phosphite, and up to about10.0 per cent by weight of the residue which remains after removal ofthe solvent from the extract obtained by extracting a petroleumdistillate oil with a solvent capable of removing polycyclichydrocarbons and sulfur compounds from petroleum distillate oils, saidresidue having a viscosity between about 55 an phite, and about 1.0 percent by weight of the residue which remains after removal of thefurfural from the extract. obtained by extracting a petroleum distillateoil with furfural, said residue having a viscosity betweenabout 55 andabout 70 SUV at 210 F.

' BENJAMIN F. HUNTER.

HAROLD P. HOBART.

' Certificate of Correction Patent No. 2,413,353. December 31, 1946.BENJAMIN F. HUNTER ET AL. It is hereby certified that error appears inthe printed specification of the above numbered patent requiringcorrection as follows: Column 6, line 21, claim 2, for

5.0 per cent read 50.0 gar cent; and that the said Letters Patent shouldbe read with this correction therein t at the same may conform to therecord of the case in the Patent Oflice.

Signed and sealed this 4th day of March, A. D. 1947.

LESLIE FRAZER,

First Assistant Uommz'uioner of Patents.

